package com.juyu.reader.author.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;

/** * 3DES加密工具类 */
public class DES3 {
	// 向量
	private final static String iv = "01234567";
	// 加解密统一使用的编码方式
	private final static String encoding = "utf-8";

	/**
	 * * 3DES加密 ** @param plainText 普通文本 *
	 * 
	 * @return * @throws Exception
	 * 
	 **/
	public static String encode(byte[] plainByte, String key) throws Exception {
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key.getBytes());
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");

		deskey = keyfactory.generateSecret(spec);
		Cipher cipher = Cipher.getInstance("desede/CBC/PKCS5Padding");
		IvParameterSpec ips = new IvParameterSpec(iv.getBytes());
		cipher.init(Cipher.ENCRYPT_MODE, deskey, ips);
		byte[] encryptData = cipher.doFinal(plainByte);
		return Base64.encode(encryptData);
	}

	/** * 3DES解密 ** @param encryptText 加密文本 * @return * @throws Exception */

	public static String decode(byte[] encryptByte, String key) throws Exception {
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key.getBytes());
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
		deskey = keyfactory.generateSecret(spec);
		Cipher cipher = Cipher.getInstance("desede/CBC/PKCS5Padding");
		IvParameterSpec ips = new IvParameterSpec(iv.getBytes());
		cipher.init(Cipher.DECRYPT_MODE, deskey, ips);
		byte[] decryptData = cipher.doFinal(Base64.decode(new String(encryptByte, "utf-8")));
		return new String(decryptData, encoding);
	}

	public static String padding(String str) {
		byte[] oldByteArray;
		try {
			oldByteArray = str.getBytes("UTF8");
			int numberToPad = 8 - oldByteArray.length % 8;
			byte[] newByteArray = new byte[oldByteArray.length + numberToPad];
			System.arraycopy(oldByteArray, 0, newByteArray, 0, oldByteArray.length);
			for (int i = oldByteArray.length; i < newByteArray.length; ++i) {
				newByteArray[i] = 0;
			}
			return new String(newByteArray, "UTF8");
		} catch (UnsupportedEncodingException e) {
			System.out.println("Crypter.padding UnsupportedEncodingException");
		}
		return null;
	}

	/** * Base64编码工具类 * */
	public static class Base64 {
		private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
				.toCharArray();

		public static String encode(byte[] data) {
			int start = 0;
			int len = data.length;
			StringBuffer buf = new StringBuffer(data.length * 3 / 2);
			int end = len - 3;
			int i = start;
			int n = 0;
			while (i <= end) {
				int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 0x0ff) << 8)
						| (((int) data[i + 2]) & 0x0ff);
				buf.append(legalChars[(d >> 18) & 63]);
				buf.append(legalChars[(d >> 12) & 63]);
				buf.append(legalChars[(d >> 6) & 63]);
				buf.append(legalChars[d & 63]);
				i += 3;
				if (n++ >= 14) {
					n = 0;
					buf.append(" ");
				}
			}
			if (i == start + len - 2) {
				int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 255) << 8);
				buf.append(legalChars[(d >> 18) & 63]);
				buf.append(legalChars[(d >> 12) & 63]);
				buf.append(legalChars[(d >> 6) & 63]);
				buf.append("=");
			} else if (i == start + len - 1) {
				int d = (((int) data[i]) & 0x0ff) << 16;
				buf.append(legalChars[(d >> 18) & 63]);
				buf.append(legalChars[(d >> 12) & 63]);
				buf.append("==");
			}
			return buf.toString();
		}

		private static int decode(char c) {
			if (c >= 'A' && c <= 'Z')
				return ((int) c) - 65;
			else if (c >= 'a' && c <= 'z')
				return ((int) c) - 97 + 26;
			else if (c >= '0' && c <= '9')
				return ((int) c) - 48 + 26 + 26;
			else
				switch (c) {
				case '+':
					return 62;
				case '/':
					return 63;
				case '=':
					return 0;
				default:
					throw new RuntimeException("unexpected code: " + c);
				}
		}

		/**
		 * * Decodes the given Base64 encoded String to a new byte array. The
		 * byte array holding the decoded data is returned.
		 */
		public static byte[] decode(String s) {
			ByteArrayOutputStream bos = new ByteArrayOutputStream();
			try {
				decode(s, bos);
			} catch (IOException e) {
				throw new RuntimeException();
			}
			byte[] decodedBytes = bos.toByteArray();
			try {
				bos.close();
				bos = null;
			} catch (IOException ex) {
				System.err.println("Error while decoding BASE64: " + ex.toString());
			}
			return decodedBytes;
		}

		private static void decode(String s, OutputStream os) throws IOException {
			int i = 0;
			int len = s.length();
			while (true) {
				while (i < len && s.charAt(i) <= ' ')
					i++;
				if (i == len)
					break;
				int tri = (decode(s.charAt(i)) << 18) + (decode(s.charAt(i + 1)) << 12) + (decode(s.charAt(i + 2)) << 6)
						+ (decode(s.charAt(i + 3)));
				os.write((tri >> 16) & 255);
				if (s.charAt(i + 2) == '=')
					break;
				os.write((tri >> 8) & 255);
				if (s.charAt(i + 3) == '=')
					break;
				os.write(tri & 255);
				i += 4;
			}
		}
	}
}
